Assuming that co-distributed species are exposed to similar environmental conditions, ecological niche models (ENMs) of bird and plant species inhabiting tropical dry forests (TDFs) in Mexico were developed to evaluate future projections of their distribution for the years 2050 and 2070. We used ENM-based predictions and climatic data for two Global Climate Models, considering two Representative Concentration Pathway scenarios (RCP4.5/RCP8.5). We also evaluated the effects of habitat loss and the importance of the Mexican system of protected areas (PAs) on the projected models for a more detailed prediction of TDFs and to identify hot spots that require conservation actions. We identified four major distributional areas: the main one located along the Pacific Coast (from Sonora to Chiapas, including the Cape and Bajío regions, and the Balsas river basin), and three isolated areas: the Yucatán peninsula, central Veracruz, and southern Tamaulipas. When considering the effect of habitat loss, a significant reduction (~61%) of the TDFs predicted area occurred, whereas climate-change models suggested (in comparison with the present distribution model) an increase in area of 3.0-10.0% and 3.0-9.0% for 2050 and 2070, respectively. In future scenarios, TDFs will occupy areas above its current average elevational distribution that are outside of its present geographical range. Our findings show that TDFs may persist in Mexican territory until the middle of the XXI century; however, the challenges about long-term conservation are partially addressed (only 7% unaffected within the Mexican network of PAs) with the current Mexican PAs network. Based on our ENM approach, we suggest that a combination of models of species inhabiting present TDFs and taking into account change scenarios represent an invaluable tool to create new PAs and ecological corridors, as a response to the increasing levels of habitat destruction and the effects of climate change on this ecosystem.

Neotropical seasonally dry forests (NSDFs) are widely distributed and possess high levels of species richness and endemism; however, their biogeography remains only partially understood. Using species distribution modelling and parsimony analysis of endemicity, we analysed the distributional patterns of the NSDF avifauna in order to identify their areas of endemism and provide a better understanding of the historical relationships among those areas. The strict consensus trees revealed 17 areas of endemism for NSDFs, which involve four large regions: Baja California, Caribbean–Antilles islands, Mesoamerica and South America. These well‐resolved clades are circumscribed by geographical and ecological barriers associated with the Gulf of California, the leading edge of the Caribbean plate, the Tehuantepec Isthmus, the Polochic–Motagua fault, the Nicaragua Depression, the Chocó forest, the Amazon basin and the Andean Cordillera. Relationships among groups of NSDFs found here suggest that evolution of their avifauna involved a mixture of vicariance and dispersal events. Our results support the idea of independent diversification patterns and biogeographical processes in each region, including those previously associated with the Pleistocene Arc Hypothesis for NSDFs of south‐eastern South America. This study provides a biogeographical framework to open new lines of research related to the biotic diversification of NSDFs.

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New World orioles (Icterus) include several closely related species and subspecies pairs that provide excellent opportunities for studying recent speciation. We examined a subspecies pair in the Orchard Oriole group: Orchard Oriole (I. spurius spurius), a long-distance migrant that breeds in eastern North America, and Fuertes’s Oriole (I. s. fuertesi), a short-distance migrant that breeds in a restricted range in Veracruz, Mexico. We sequenced parts of the mitochondrial cytochrome-b gene (925 base pairs) and control region (344 base pairs) from 23 Orchard Orioles and 7 Fuertes’s Orioles. Subspecies are not reciprocally monophyletic. Instead, our data suggest that at least one taxon is paraphyletic or polyphyletic. We found little support for any further phylogenetic structure, including whether one subspecies might be derived from the other. However, haplotype frequency analysis suggests that there is little or no current gene flow between the taxa. The phylogenetic relationship between Orchard and Fuertes’s orioles is likely a result of recent divergence and incomplete lineage sorting. That interpretation is consistent with theoretical models of speciation, which predict patterns of nonmonophyly at early stages of taxon divergence. Our findings suggest that Orchard and Fuertes’s orioles are separate species and provide a case study for evaluating the importance of monophyly in defining species limits.

Aim The Mexican Transition Zone (MTZ) is an area where the Nearctic and Neotropical biogeographical regions overlap, generating high species richness and endemism. The objective of this study was to analyse if potential changes in the composition and the geographical location of areas of endemism (AEs) for beetles and mammals during the Last Glacial Maximum (LGM), the mid‐Holocene (MH) or the Last Interglacial (LIG) have influenced the definition of the MTZ in the present. Location Mexico and Central America. Methods Ecological niche models (ENM) were generated describing the current distribution of 218 species associated with the MTZ and then transferred to three periods into the past. A parsimony analysis of endemicity (PAE) was run to identify current AEs. The transferred models of each set of species that form the current AEs were used to assess if the geographical ranges of the species’ ecological niches changed over time, or whether they remained stable supporting the validation of the AEs during three past recent periods (LGM, MH and LIG). Results Two current AEs were detected that persisted geographically during the three past periods (LGM, MH and LIG). Main conclusions The results show that some AEs change through time as a response of climate, whereas others remained stable. Thus, the MTZ could be considered as a dynamic zone at least over the last 130,000 years. The climate analysis of the AEs allows them to be recognized either as true spatio‐temporal units, or as temporarily restricted patterns of co‐distribution resulting from changes in climate over time.